Key A - Monocotyledons
The plants that most people readily recognize as flowering plants (i.e. excluding conifers, ferns and the like) are collectively known as Angiosperms. This group can further be split into two smaller groups - the monocotyledons and the dicotyledons. The cotyledon is the technical term for what is essentially a storage organ to provide 'food' for the germinating seedling - a bit like the yolk of a chicken egg. As may be deduced from the names, monocotyledonous plants have one cotyledon, while dicotyledonous plants have two cotyledons. Once the plants are growing and the cotyledons have shriveled, other common features may be used to distinguish the two groups from each other.
Monocotyledons have a number of common traits. Their leaves tend to have veins that run from the base of the leaf to the tip and usually run parallel to each other; the veins usually do not produce regular branching or netted venation. The flower parts of monocotyledons tend to be arranged in threes or sixes. The style of growth of monocotyledons tends to preclude the ability to produce secondary thickening, so these plants rarely form trees as they cannot form bark. Plants that have evolved a novel approach to this include palms and some of the yuccas. The monocotyledon group includes all of the grasses, sedges, rushes and allies, most bulb-forming plants and many aquatic plants. Typically, many of these have elongated, narrow leaves that we would term 'grass-like'. The grass, sedges and rushes tend to have rather understated flowers that are largely wind-pollinated, but the bulb-bearing species often put on a spectacular show when flowering and include many of our most popular spring garden plants.
Important Note: The keys only include species that have been recorded in southern New Jersey. Care should therefore be taken if using these keys outside of this area, as there may be other species present that are not included in the keys.
1. Petalless flowers inclosed, or spikes of flowers surrounded by, overlapping husk-like scales (glumes); plants grass-like.
2. Stems hollow, round or flattened in cross-section but not triangular, anthers attached by the middle........................................Grasses
2. Stems solid, more or less triangular in cross-section, anthers attached at the base.........................................................................Sedges
1. Flowers not inclosed in husk-like glumes.
3. Aquatic plants, entirely submerged or with some of the leaves floating on the surface.
4. Plant a small floating disc with several roots below, or a minute floating globule.............................................................. Duckweeds
4. Plant not a small floating disc or globule
5. Stems branched and leafy, leaves long and grass-like or ovate.
6. Flowers inconspicuous, axillary or in short spikes..................................................................................................................Najads
6. Flowers star-like, yellow, raised above the surface on slender pedicels.................................................................. Mud-plantains
5. Stems not branched and leafy.
7. Stems mostly simple, leaves short, linear, whorled......................................................................................................Waterweeds
7. Plant more or less stemless, leaves arising from the base.
8. All leaves from the root, long and ribbon-like, flowers on separate thread-like stems.............................................. Tape-grass
8. Leaves basal in an erect tuft, lanceolate, flat or awl-shaped, flowers projecting above the surface.
9. Flowers showy, white, in an open, whorled spike.................................................................................................. Arrowheads
9. Flowers minute, packed together into a compact, button-like head......................................................................... Pipeworts
3. Erect plants or vines, growing in water, swamps or dry ground.
10. Woody vines, or upright herbs with tendrils. Flowers greenish.
11. Flowers in umbels, stems often woody and armed with spines; fruit a berry................................................................. Greenbriers
11. Flowers in panicles or racemes; fruit dry, winged........................................................................................................................ Yams
10. Not woody vines, or upright herbs with tendrils.
12. Flowers irregular, the petals not all of similar size and shape.
13. Flowers slightly irregular, the lateral two petals larger than lower one. Included in a folded leaf-like bract.............Day-flowers
13. Flowers markedly irregular, lower petal modified into a more or less elaborate lip, lateral petals much smaller, sepals slender
and alike............................................................................................................................................................................... Orchids
12. Flowers regular, all petals of similar size and shape.
14. Leaves in whorls around the stem, or palmately lobed.
15. Leaves one or two, palmately divided.................................................................................................................................Arums
15. Leaves in whorls around the stem.
16. Leaves in one whorl of three, flowers solitary..............................................................................................................Trilliums
16. Leaves in two or more whorls.
17. Leaves in two whorls of more than three, flowers several............................................................. Indian Cucumber-root
17. Leaves in many whorls, flowers large, red or orange..................................................................................................... Lilies
14. Leaves not whorled or palmately divided.
18. Leaves all radical (emerging from the base, not up the stem).
19. Leaves sagittate (shaped like an arrow head).
20. Flowers white, in an open, whorled spike......................................................................................................... Arrowheads
20. Flowers not white.
21. Flowers blue, in a compact spike................................................................................................................ Pickerelweed
21. Flowers minute, compacted into an upright, cigar-like spike (spadix) incased in a outer spathe.........................Arums
19. Leaves not sagittate.
22. Leaves oval or ovate, at least 25 mm. wide.
23. Leaves more than two.
24. Flowers minute, on a fleshy, rounded or cigar-like spadix, with no sepals or petals.
25. Spadix covered by a hood-like spathe, appearing before the large, cabbage-like leaves................ Skunk-cabbage
25. Spadix exposed, bright yellow, leaves usually floating...........................................................................Golden-club
24. Flowers with obvious petals and sepals, mostly showy.
26. Flowers white.
27. Flowers in a much-branched, whorled panicle, each flower relatively small-petalled..............Water-plantains
27. Flowers in a whorled spike, petals relatively large.............................................................................Arrowheads
26. Flowers pink, in a dense spike............................................................................................................... Swamp-pink
23. Leaves only two.
28. Flowers single, lily-like, yellow; leaves spotted........................................................................................... Trout-lilies
28. Flowers white, clustered in a rounded head, plant garlic scented, leaves absent at flowering time....American Leek
22. Leaves grass-like or long linear, less than 25 mm. wide.
29. Flowers solitary.
30. Flowers with six outer petals and an inner set fused into a tube. White and/or various shades of yellow....Daffodils
30. Flowers not as above.
31. Flowers white with green patches, nodding or hanging downward.........................................................Snowdrops
31. Flowers not as above.
32. Six Petals fused at base into a long tube, opening at the top; leaves with central silver stripe...............Crocuses
32. Flowers pale bluish or pinkish-purple with darker central stripe............................................Spring Starflower
29. Flowers not solitary.
33. Flowers in a remotely whorled spike or an umbel...................................................................................... Arrowheads
33. Flowers not in a remotely whorled spike or an umbel.
34. Flowers in a slender continuous spike.
35. Leaves broadly or narrowly grass-like.
36. Leaves narrowly grass-like, erect, flowers minute (spike resembling that of a plantain).............Arrowgrasses
36. Leaves broadly grass-like, strongly arching over. Flowers pale purple or pinkish in a showy spike.....Lilyturfs
35. Leaves lanceolate spatulate, forming a rosette, flowers white, bellshaped, mealy................................ Colicroots
34. Flowers not in a slender continuous spike.
37. Flowers in a globular compact head.
38. Head white, button-like, flowers minute............................................................................................ Pipeworts
38. Head of tightly overlapping brown scales, flowers protruding, conspicuous, yellow..... Yellow-eyed-grasses
37. Flowers not in a globular compact head (if appearing to be so, then whole plant rush-like).
39. Flowers conspicuous, star-shaped, in an open panicle.
40. Flowers white, leaves hairless........................................................................................ Star-of-Bethlehems
40. Flowers yellow, leaves hairy.........................................................................................................Star-grasses
39. Flowers inconspicuous, in an open panicle, scattered singly or clustered in heads (panicle sometimes
compact), green or brownish. Leaves grass-like or awl-shaped; whole plant resembling a sedge.......... Rushes
18. Leaves present along the stems.
36. Leaves oval, ovate, or otherwise rounded, not grass-like (at least 25 mm. wide).
37. Flowers green, in a large open panicle....................................................................................... Green False-helleborine
37. Flowers not green.
38. Flowers blue, leaves sagittate...................................................................................................................... Pickerelweed
38. Flowers white or yellow.
39. Flowers white, star-shaped, tiny, in a compact terminal panicle......................................... Maianthemum species
39. Flowers white or yellow, bell-shaped.
40. Flowers solitary, cream or yellow............................................................................................................... Bellworts
40. Flowers in racemes, or clustered along the stem.
41. Flowers in clusters of two or more, creamy white..................................................................... Solomon's-seals
41. Flowers in a one-sided spike, pure white.................................................................................. Lily-of-the-valley
36. Leaves grass-like or long linear (less than 25 mm. wide).
42. Flowers without petals or sepals, packed tightly into elongate or rounded structures that may not be immediately
apparent as flowers.
43. Flowers in globular umbels of stamens or stigmas, like bristly pompoms on a stalk......................................Bur-reeds
43. Flowers in compact, upright spikes.
44. Flowers in dense, terminal spikes, dark brown..................................................................................................Cattails
44. Flowers yellowish or greenish, in a slender, dense spike (a spadix) on the side of a flat, leaf-like stem.... Sweet-flag
42. Flowers with usually conspicuous petals and sepals. If petals and sepals inconspicuous, then plants rush-like.
45. Flowers with colorful and conspicuous petals - not rush-like.
46. Flowers in a narrow, upright spike.
47. Flowers yellow, with chaffy bracts................................................................................ American Bog-asphodel
47. Flowers white or greenish-white.
48. Stem sticky to the touch.................................................................................... Coastal Plain False-asphodel
48. Stem not sticky to the touch.
49. Leaves grass-like, coarse, in a dense tuft................................................................... Eastern Turkey-beard
49. Leaves linear, 18 mm.broad, smooth.............................................................................................. Fly-poison
46. Flowers not in a narrow, upright spike.
50. Flower stems covered in woolly hairs.
51. Flowers pale yellow, clustered close together....................................................................... Carolina Redroot
51. Flowers consisting most notably of a dense tuft of bright yellow hairs......................................... Goldencrest
50. Stems not woolly; flowers in an umbel, panicle, open spike, or solitary at the top of the stem.
52. Flowers in an umbel, panicle or open spike; stems round, not winged.
53. Sepals small, green and leaf-like, beneath three brightly-colored petals................................... Spiderworts
53. Sepals and petals similar, giving impression of six petals.
54. Flowers white or greenish, in an open spike or branched panicle............................. Bunchflower family
54. Flowers pink or white, clustered at the top of the stem; garlic or onion smell....................Allium species
52. Flowers solitary or, if in an umbel, then stems flattened and winged................................................Iris family
45. Flowers with inconspicuous perianth, green or brownish, in an open (or congested) panicle; scattered singly or
clustered in heads. Leaves grass-like or awl-shaped; whole plant resembling a sedge.....................................Rushes